Dynamo-electric machine.



D. C. JACKSON. DYNAMO ELECTRIC MACHINE.

APPLICATION FXLED DEC. 22, 1902.

1,106,514. Patented Aug. 11, 19m

IN A C unrrni) STATES,

PATENT 0mm DUGALD c. JACKSON, or MADISON, Wisconsm.

chines, and has for its object improved means for. controlling such machinesand for varying the speed thereof. h

Although applicable to electric motors and to generators, I have, for illustration,

shown my invention as applied to electric motors and have shown improved means for controlling such motors and for regulating and varying the speed or pressure thereof, especially when such motors are-operated as series machines in connection with a constant pre sure alternating current circuit, or when coilnected with such circuit similarly to a. dire t current shunt motor, the armature circuit and the field circuit being connected-Yin independent branches in shunt of the supply,circuit. \Vhen such motor is intended for operation as a series machine,

I preferably control and vary the speed thereof by introducing into the motor circuit an adjustable impedance. To further control the speed, and also to regulate the torque exerted by the motor, I preferably connect an adjustable impedance in shunt of the brushes. Thus, by a proper adjustment of said impedance, effective and ethcient control is obtained. Instead of being directly connected to supply mains, a separate transformer, or an independent secondary of one transformer, may be interposed in each branch. To prevent excessive and'injurious sparking, which is likely to occur in connection with a commutator of such a motor as I describe, I preferably electrically connect together the commutator segments.

I have once to single phase electric machines, as it is particularly advantageous when such machines are employed, although it is evident that it may also be effectively employed in connection with polyphase' machines and DYNA ro-ELncTRIc MACBZINE.

Specification of Letters Patent.

Application filed December 22,1902. Serial No. 186,148. v

circuits. In connectiomwith described my invention with refer- Patented Aug. 1' 1, 1914.

ghase bircuits, the fields. of the motor 5 ould be wound III the 'usua-l m'ann'er appropriate for the number of phases, and the number bf brushes should preferably .be equal to' the normal number ofjcircu t Wire's; namelythree brushes" for a th'i ee-,phase circuit, four, brushes ,for a two-phase circuit',ffend ,so' on, the brushes being'pioperlygspa dovepthe commutator. is appl e s imnne gw t fimyl l8 '(,0;Q ren 8202,

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ii sl is di z fi V c, i .motor and devices ,arrangedjnec'ordance with my Q invention, the 'mot'o'i' jb eing' 'connected to runas-aseriesinotor. I: .2 shows a modi-fied commutator constriction, Fig. 3 shows a modificd'g 'form ofzcommutated winding, which maybe employed. v Like character's ofreferencejndieate like parts in the severe V. gu1ies .f' A source 1 supplies "alternating curtent through conductors wand b, to a 'field'winding 2, distributed over a ,field"ring,3fof,an1

alternating current motor 4, and to an 'ar- 'ma ture winding 5, distributed over an armature 6. I also preferably employrupon said armature a short circuited windin ,preferably of the squirrel-cage type an ing of conductors 7, 7, and short circuiting consistrings 8. The armature windingo, is referably connected at intervals by con uctors 9, 9 to a commutator 10' consisting of seg: ments 11, 11, and engag by-brushes 12", 12.

I preferably include in the main supply conductor a, an adjustable} impedance 13, and for 'the same object and alsojo'lregulate' the torque, I preferably emplo yjlan additional adj ustable impedance 14, adapted to be connected in shunt of the brushes 12, 12 'Eflicient regulation is thus obtained by adjusting the'mgin current supply. by means of impedance 13, and by fl(l]l1$t1llg the current supply through the closed circuit winding 5 on the armature, by means of the shunting impedance 1}. The shunting impedance 14 has a direct relation to the extent of induc magnetic field and the induced currents produced in the short circuited winding.

,The word impedance, referring to the adjustable controlling impedances 13, and 14, is used in the broad sense, meaning resistance alone, or reactance alone, or the two used comomtly.

In a motor arranged as described, there is apt to be excessive and injurious sparking,

.and as a reventive means I connect resistances in ridge between commutator segments. These resistances may be contained in coils 20, for instance, colls of German silver wire, bridged across the segments, as

shown in Fig. 1, but as an alternative means for obtaining such resistance effect, I employ a commutator of modified construction, as shown in Fig. 2. A core is slitted to form suitable segments, the slits 21 being cut to within a thin section 22 of completion, such thin section containing the resistance necessary to prevent undue sparking between adjacent commutator segments. The commutator thus forms a continuous closed conductor. The slits may be filled up with insulating materiaij, or may be made complete and filled up with some high resistance material to accomplish the same result as the thin section 22. Besides being a preventive means for sparln'ng, these bridging resist-' ances between segments give the -commutated winding 5 the effect of a short-circuited winding.

In Fig 3 I have shown a modified form of. 'commutated armature winding, having open coils 23 connected star. fashion, as shown. Any other suitable windings might also beemployed.

. .Having thus described my invention, I claim as new, and desire to secure by Letters Patent:

1. In an alternatin current motor the combination with a fie d winding, of a commutated armature circuit included in series lurahty of Y resistances therewith, and a bridging coils of said armature circuit, substantially as described.

2. In an alternatiu current motor the combination with a eld winding, of an said commutated windiiig, substantially as described- 3. In an alternating current motor, the combination with a field winding, of a commutated armature circuit included in series therewith, a plurality of conducting branches, bridging coils of said armature circuit, and variable impedance adapted for inclusion' in parallel with the commutated circuit, substantially as described.

4. In an alternating current motor, the combination with a field winding, of an armature'provided with a normally shortcircuited winding, and with a commutated winding adapted for inclusion in circuit in series with said field winding, a plurality of conducting. branches brid 'ngcoils of said commutated winding, an means for varying the current in said field winding, substantially as-described.

5. In an alternating current dynamo electric machine, the combination with a field winding, of a source ofalternating current,

a commutated. armature winding connected in series with said source and with said field winding, a segmented commutator to which said windingis connected at suitable inter vals in order to produce series motor torque, and means tor electrically bridging segments of saidcommiitatort" 6. In an alternating current dynamo electric machine, the combination with afield winding, of'a source of alternating current, an armature winding short cir'cuited on it self to produce induction motor torq ue, an

auxiliary commutated armature winding connected in series with said source and with said field winding, a segmented commutator to which said commutated winding is connected at suitable intervals to produce series motor torque, and means for electrically bridging segments of said commutator.

7. The combination with a source of alternating currents, of a motor receiving current from said sourcepmeans for varying said current, a field winding for said motor, an armature for said motor provided with a short circuitcd winding and with a commutated Winding, the commutated circuit being included in series with said field winding, impedance in parallel circuit with the commutated circuit, and means for varying said impedance.

In witness whereof, I hereunto subscribe my name this seventeenth day of December DUGALD C. JACKSON. Witnesses:

LYNN A. WILLIAMS, HARVEY L. Hanson.

0091:: of thii patent may be obtained for live cents each. by addressing the Commissioner of iatenu,

. Washington, D. 0- 

